Optical fibers have greatly enhanced the capabilities of modern telecommunication systems by vastly increasing communication bandwidths, reducing costs, and improving reliability. Because of the limits of fiber technology and state-of-the-art input/output devices, however, current photonic communication links operate at bandwidths far below those that are theoretically possible.
Wavelength division multiplexing devices, such as the prior art apparatus illustrated schematically in FIG. 1, have been investigated for transmission of images through single mode fibers. Wavelength division multiplexing device 10 couples a plurality of input fibers to a single mode optical transmission fiber 11. The input fibers provide input light from a collection of modulated optical sources, such as semiconductor laser diodes, each emitting at a unique wavelength, such as .lambda..sub.1, .lambda..sub.2, .lambda..sub.3, .lambda..sub.4, and .lambda..sub.5, for example. The input light is coupled to single mode transmission fiber 11 by means of a collective array of grating couplers 12, 14, 16, and 18. At the receiving end of transmission fiber 11, a dispersive array of grating couplers 13, 15, 17, and 19 separate the light into its wavelength components .lambda..sub.1, .lambda..sub.2, .lambda..sub.3, .lambda..sub.4, and .lambda..sub.5, which are output on separate optical fibers as illustrated.
Although the bandwidth capabilities of single mode optical transmission fibers can be realized by the foregoing technique, wavelength division multiplexing device 10 does not fully address the possible relationships among the information being transmitted over the parallel wavelength channels, which is an important aspect of parallel communication channels. Therefore, an improved single mode optical fiber image transmission system is needed to operate at high bandwidths with low attenuation while exploiting the parallel nature of the information being transmitted.